Wireless communications base stations include a distributed base station. The distributed base station includes a baseband unit (BBU), an radio remote unit (RRU), and an antenna. When a network is actually built, power supplied to a radio remote unit is a direct current provided by a remote power system. As shown in FIG. 1, a radio remote unit is connected to a remote power system by using a direct current power cable. Generally, the remote power system is 40 to 100 meters, or even farther away from the radio remote unit.
During building of a wireless communications network, after a distributed base station is deployed in an initial phase, radio remote units are gradually added in the next few years to increase a capacity of the base station. Therefore, when the radio remote units are added, direct current power cables connected to the radio remote units also need to be added. As shown in FIG. 2, if a quantity of radio remote units on a distributed base station is increased from originally 3 to 6, three direct current power cables need to be synchronously added.
However, it is well known that a laying length of a direct current power cable is about 40 to 100 meters, or even longer, and laying direct current power cables requires relatively high engineering costs and a long construction period. In addition, because a direct current power cable is located outdoors, the entire direct current power cable needs to be protected, and costs are high. Therefore, when a capacity of a base station is expanded by adding radio remote units, direct current power cables connected to the radio remote units need to be synchronously added. In this case, engineering costs of laying direct current power cables and costs for late-stage protection need to be increased.